1. Field of the Invention
Embodiments of the present invention generally relate to the fabrication of integrated circuits, and more particularly, to a process for depositing dielectric layers on a substrate.
2. Description of the Related Art
Integrated circuit geometries have dramatically decreased in size since such devices were first introduced several decades ago. Since then, integrated circuits have generally followed the two year/half-size rule (often called Moore""s Law), which means that the number of devices on a chip doubles every two years. Today""s fabrication facilities are routinely producing devices having 0.13 micrometer and even 0.1 micrometer feature sizes, and tomorrow""s facilities soon will be producing devices having even smaller feature sizes.
The continued reduction in device geometries has generated a demand for films having lower k values because the capacitive coupling between adjacent metal lines must be reduced to further reduce the size of devices on integrated circuits. In particular, insulators having low dielectric constants (k), less than about 4.0, are desirable. Examples of insulators having low dielectric constants include carbon doped silicon oxide (SiCOH), fluorine-doped silicon glass (FSG) and polytetrafluoroethylene (PTFE).
Rose et al. (U.S. Pat. No. 6,068,884) proposed a method for depositing an insulator by partially fragmenting a cyclic organosilicon compound to form both cyclic and linear structures in the deposited film. However, partially fragmenting cyclic precursors is difficult to control and thus, product consistency is difficult to achieve.
Therefore, a need exists for an improved method for depositing films with lower dielectric values.
Embodiments of the present invention are generally directed to a method of depositing a low dielectric constant film on a substrate. In one embodiment, the method includes the steps of positioning the substrate in a deposition chamber, providing a gas mixture to the deposition chamber, in which the gas mixture is comprised of one or more cyclic organosilicon compounds, one or more aliphatic compounds and one or more oxidizing gases. The method further includes reacting the gas mixture in the presence of an electric field to form the low dielectric constant film on the semiconductor substrate. The electric field is generated using a very high frequency power having a frequency in a range of about 20 MHz to about 100 MHz.
In another embodiment, the present invention is directed to a method of depositing a low dielectric constant film on a substrate, which includes positioning the substrate in a deposition chamber and providing a gas mixture to the deposition chamber. The gas mixture includes one or more cyclic organosilicon compounds, one or more aliphatic compounds, one or more meta-stable organic compounds and one or more oxidizing gases. The method further includes reacting the gas mixture in the presence of an electric field to transform the meta-stable organic compound to an unstable component within a network of the film. The electric field is generated using a very high frequency power having a frequency in a range of about 20 MHz to about 100 MHz. The method also includes annealing the film to remove the unstable component from the film.